Burial vaults are made of concrete so that the vaults can withstand the weight of the earth cover, can withstand the added weight of earth-handling machinery, and can withstand water pressure and other forces from the surrounding earth. The main advantages of concrete are high strength at low cost, and ease of construction by casting means, well known in the art, which involve only a few manufacturing steps. Concrete however does not provide a sufficient barrier to keep water and other matter from penetrating into the vault, and concrete does not have a satisfactorily pleasing appearance.
In order to provide a better barrier to flow of matter into the burial vault, several schemes for cladding concrete burial vaults with plastic have been proposed. The key features in these proposals are the adhering means at the plastic to concrete interface. Chandler's U.S. Pat. No. 3,439,461 proposes applying a wet and tacky adhesive onto the surfaces of a plastic mold before filling the mold with concrete so that the adhesive and the concrete will cure together and be bonded at the interface. McQuestion's U.S. Pat. No. 3,839,768 seeks to overcome the added manufacturing steps which are required to use adhesive as the adhering means at the plastic to concrete interface. To do this McQuestion proposes to attach fiberglass loops to the surfaces of a plastic mold so that, when the mold is filled with concrete, the loops will be embedded in the concrete. In U.S. Pat. No. 4,060,581 Darby seeks to overcome the problem where at least some of the wet and tacky adhesive pre-applied to surfaces of a plastic mold is scrubbed away when the concrete is poured into the mold. Darby proposes to adhere aggregate to surfaces of the plastic mold so that when the mold is filled with concrete and the concrete cured the pre-applied aggregate provides the adhering means at the plastic to concrete interface. Juba's U.S. Pat. No. 4,128,981 proposes using a dry adhesive to minimize the scrubbing problem.
All of these proposals require preparation of special adhering means at the interface between surfaces of the plastic mold and the concrete fill and thereby these proposals need a number of manufacturing steps which take special care to insure that the interface bond will have the strength needed for burial vaults. Thus, there is an opportunity to devise a concrete filled container burial vault in which the links tying the concrete to a container are provided by the structure of the container itself, which needs less manufacturing steps, and for which the manufacturing steps are all well known in the art and do not require special care.